With high integration of semiconductor devices, a process technique of more finely processing semiconductor devices is requested. As a technique of finely processing semiconductor devices, a pattern forming method has been generally used, in which a resist pattern is formed using a photolithography technique and the formed resist pattern is used as an etching mask to etch a workpiece.
It has been recently requested that semiconductor devices be miniaturized to a resolution limit or smaller of an exposure device in the photolithography technique.
As a technique of forming a finer pattern than the resolution limit of an exposure device by the photography technique, a double patterning technique such as a lithography-etching-lithography-etching (LELE) method is known (e.g., see Japanese Laid-Open Patent Publication No. 2009-288344).